<!doctype html>
<html>
  <head>
    <title>sign-here demo</title>
     <meta name="format-detection" content="telephone=yes">
    <meta name="viewport" content="width=device-width, maximum-scale=1.0, user-scalable=no">
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <script type="text/javascript" src="/static/ajz/js/jquery.min.js" ></script>
    <style type="text/css">
    
html,body{
    width: 100%;
    height: 100%;
    background-color:#FFF;
}
p{
    margin:0px;
    padding:0px;
}
@media only screen and (min-width: 100px) and (max-width:330px){
  #clearCanvas{
    width: 99.9%;
    height: 40px;
    line-height: 40px;
    text-align: center;
    float: left;
    border: 1px solid #DEDEDE;
    position: fixed;
    left: -39%;
    top: 4.4%;
    transform:rotate(90deg);
    -ms-transform:rotate(90deg);
    -moz-transform:rotate(90deg);
    -webkit-transform:rotate(90deg);
    -o-transform:rotate(90deg);
  }
}
#canvas{
    width: 100%;
    height: 100vh;
    float: left;
    touch-action: none;
    -o-touch-action: none;
    -ms-touch-action: none;
    -moz-touch-action: none;
    -webkit-touch-action: none;
    /*移动端 触摸时 不允许用户进行操作 （也就是禁用滑动，缩放页面和元素等）*/
}
#canvas canvas{
    /*display: block;*/
    width: 100%;
    height: 100vh;
}
#clearCanvas{
    width: 99.9%;
    height: 40px;
    line-height: 40px;
    text-align: center;
    float: left;
    border: 1px solid #DEDEDE;
    position: fixed;
    left: -44%;
    top: 50%;
    transform:rotate(90deg);
    -ms-transform:rotate(90deg);
    -moz-transform:rotate(90deg);
    -webkit-transform:rotate(90deg);
    -o-transform:rotate(90deg);
}
#saveCanvas{
    width:48%;
    height: 40px;
    line-height: 40px;
    text-align: center;
    /*float: left;*/
    border: 1px solid #DEDEDE;
    position: absolute;
    left:49%;
    bottom:0px;
}
    </style>
    </head>
    <body>
    <form action="" method="post" name="" id="" enctype="multipart/form-data">
    <div id="canvas">
        <p id="clearCanvas">清除</p>
        <input type="button" value="确定" style="display:none" id="saveCanvas">
    </div>
    <input type="hidden" name="canvas_user_hiddem" value="" id="canvas_user_hiddem">
    </form>
    <script type="text/javascript">
window.onload = function() {
    new lineCanvas({
        el: document.getElementById("canvas"),//绘制canvas的父级div
        clearEl: document.getElementById("clearCanvas"),//清除按钮
        saveEl: document.getElementById("saveCanvas"),//保存按钮
        //      linewidth:1,//线条粗细，选填
        //      color:"black",//线条颜色，选填
        //      background:"#ffffff"//线条背景，选填
    });
};
function lineCanvas(obj) {
    this.linewidth = 1;
    this.color = "#000000";
    this.background = "transparent";
    for (var i in obj) {
        this[i] = obj[i];
    };
    this.canvas = document.createElement("canvas");
    this.el.appendChild(this.canvas);
    this.cxt = this.canvas.getContext("2d");
    this.canvas.width = this.el.clientWidth;
    this.canvas.height = this.el.clientHeight;
    this.cxt.fillStyle = this.background;
    this.cxt.fillRect(0, 0, this.canvas.width, this.canvas.width);
    this.cxt.strokeStyle = this.color;
    this.cxt.lineWidth = this.linewidth;
    this.cxt.lineCap = "round";
    //开始绘制
    this.canvas.addEventListener("touchstart", function(e) {
        this.cxt.beginPath();
        this.cxt.moveTo(e.changedTouches[0].pageX, e.changedTouches[0].pageY);
    }.bind(this), false);
    //绘制中
    this.canvas.addEventListener("touchmove", function(e) {
        this.cxt.lineTo(e.changedTouches[0].pageX, e.changedTouches[0].pageY);
        this.cxt.stroke();
    }.bind(this), false);
    //结束绘制
    this.canvas.addEventListener("touchend", function() {
        this.cxt.closePath();
        //给父窗口中的元素赋值
        var v = window.parent.document.getElementById("staffDzqm3");
        var c = window.parent.document.getElementById("canvar_imgbox_satdd3");
        var $v = $(v);
        var $c = $(c);
        var imgBase64 = this.canvas.toDataURL();
        $v.val(imgBase64);
        $c.attr("src",imgBase64);
    }.bind(this), false);
    //清除画布
    this.clearEl.addEventListener("click", function() {
        this.cxt.clearRect(0, 0, this.canvas.width, this.canvas.height);
    }.bind(this), false);
    //保存图片，直接转base64
    this.saveEl.addEventListener("click", function() {
        var imgBase64 = this.canvas.toDataURL();
        console.log(imgBase64);
        $('#canvas_user_hiddem').val(imgBase64);
        // alert($('#canvas_user_hiddem').val())

    }.bind(this), false);
};
// alert(window.name)
// alert($('#canvas_user_hiddem').val())
    </script>
    </body>
</html>